Technical Field
The present disclosure is generally directed to light source modules and backlight units including the same.
Description of the Related Art
In general, a liquid crystal display (LCD) is a kind of flat panel display, which displays images using electrical and optical characteristics of a liquid crystal that has physical characteristics between a liquid and a solid. The liquid crystal display is thin and light compared to other displays, and is widely used in many industries with various applications thanks to low power consumption and low driving voltage.
Meanwhile, the liquid crystal display requires a separate light source because it is a non-light-emitting device that emits light by means of external components. Accordingly, a backlight unit having a light source is provided on the back surface of the liquid crystal panel to emit light toward the entire surface of the liquid crystal display, and the light is diffused by passing through a plurality of optical sheets to then be collected on the liquid crystal panel, thereby implementing visible images.
Generally, backlight units of a liquid crystal display are divided into an edge type and a direct type depending on the arrangement of light-emitting lamps that are used as a light source.
In the direct type of backlight unit, a plurality of lamps are arranged in a row on the back surface of a liquid crystal panel to directly emit light to the entire surface of the liquid crystal panel. In the edge type, a light source is installed outside a light guide plate for guiding light, and the light emitted from the light source is incident on the entire surface of the liquid crystal panel using the light guide plate.
Meanwhile, an LED is mainly used as a light source for providing light to the light guide plate, and the backlight unit adopts a plurality of LED packages. With this LED package, the LED lamps have a light distribution in the form of a point light source. The light in the form of a point light source is converted into light in the form of a planar light source by means of the light guide plate to then be emitted.
The point light source of the LED lamps may cause non-uniformity in the amount of light incident on one side of the light guide plate. That is, the amount of light incident on the light guide plate area immediately adjacent to the LED packages becomes greater than the amount of light incident on the light guide plate area between the LED packages. As a result, a hot-spot phenomenon may occur in which some areas of the backlight are bright and some other areas thereof are dark.
In addition, the number of LEDs may be increased in order to increase the amount of light incident on the light guide plate. However, in this case, heat generated from the LEDs may cause problems, and an increase in the number of LEDs may cause an increase in the cost.